Ryan E Mewis

Department of Natural Sciences, Manchester Metropolitan University, John Dalton Building, Chester St., Manchester, M1 5GD, United Kingdom.

3 papers in the library · 13 citations · publishing 2022-2025

Papers

Guilty by dissociation: Part B: evaluation of Supercritical Fluid Chromatography (SFC-UV) for the analysis of regioisomeric diphenidine-derived Novel Psychoactive Substances (NPS).

Journal of pharmaceutical and biomedical analysis July 15, 2022 Graeme Cochrane, Jennifer K Field, Matthew C Hulme et al. 9 citations

Supercritical fluid chromatography (SFC) with a carbon dioxide and ammonium acetate gradient separates 31 novel diphenidine-derived psychoactive substances, including regioisomers, in under 10 minutes. Different stationary phases (acidic, neutral, basic) produce medium to large selectivity differences between isomers. Acidic silica phases retain diphenidines longer via electrostatic attraction, while basic phases reduce retention via repulsion. Baseline separation is achieved for six of eight substituted groups on a simple silica column. As halo-substituent size increases, resolution between ortho- and meta-isomers decreases, causing co-elution of ortho- and meta-bromodiphenidines. Elution orders differ from reversed-phase UHPLC, providing orthogonal separation, with hydrophilic compounds better retained on SFC columns.

DOI: 10.1016/j.jpba.2022.114797 Full text Diphenidines Forensic Illicit drugs Novel psychoactive substances +2

Guilty by dissociation: Part A: Development of a rapid Ultra-High Performance Liquid Chromatography (UHPLC)-MS/MS methodology for the analysis of regioisomeric diphenidine-derived Novel Psychoactive Substances (NPS).

Journal of pharmaceutical and biomedical analysis July 15, 2022 Jennifer K Field, Christine Hinz, Christopher M Titman et al. 4 citations

A rapid UHPLC-MS/MS method can detect and confirm 33 different diphenidine derivatives in solid drug samples. The method separates compounds based on the position and type of chemical substituents on the phenyl ring, and it works even when common adulterants are present. The 10-minute protocol was successfully used to identify psychoactive components in four seized drug samples from law enforcement.

DOI: 10.1016/j.jpba.2022.114798 Full text Diphenidines Forensic Illicit drugs Novel psychoactive substances +2

Synthesis and crystal structures of five fluorinated diphenidine derivatives.

Acta crystallographica. Section E, Crystallographic communications March 1, 2025 Ryan E Mewis, Matthew C Hulme, Jack Marron et al.

Five fluorinated diphenidine derivatives were synthesized and their structures determined using NMR spectroscopy and X-ray crystallography. All five compounds form hydrogen bonds between their quaternary amine hydrogen atoms and chloride ions. Two compounds show N-H⋯Cl distances of 2.21–2.31 Å, while three exhibit shorter distances of 2.07–2.20 Å. The compound with a pyrrolidine ring adopts an envelope conformation, and the one with a piperidine ring adopts a chair conformation. Crystal packing in all five structures involves C-H⋯π interactions, and no π-π interactions are observed.

DOI: 10.1107/S2056989025001288 Full text Crystal structure Diphenidine Novel psychoactive substances